1. Field of the Invention
The present invention concerns a device for examining biological tissue as well as a process in which the device is employed.
The device makes possible the determination of optical characteristics of biological tissue to be examined, and it includes:                a light introduction means (for example a laser diode or the like) for introduction of visible and/or near-infrared light into the biological tissue,        a detector for converting light signals emitted from the biological tissue into detection signals,        a display or output device associated with the detector for output of information which depends upon the detection signals,        a shield or barrier associated with the detector for shielding the detector against extraneous light at least in the introduced wavelength region.        
For this, a few pointers:                the light introduction means is in practice conventionally positioned at a prescribed position relative to a predetermined light entry location associated with biological tissue,        the detector is in practice conventionally placed in a prescribed position relative to a predetermined light exit location associated with the biological tissue for detection of light following migration within the tissue and thereafter exiting the biological tissue,        the output of the information resulting from the detection signal (measurement data) can occur in any of a number of ways, for example, per display, printer, loudspeaker or the like, and        extraneous light is light which is not introduced by the light introduction means into the biological tissue to be examined.        
2. Description of the Related Art
Devices of the above described type are already known and are in particular employed for examination of traumatic intra-cranial haematoma by means of NIR-spectroscopy (NIR=near-infrared), see Claudia S. Robertson et al, Journal of Biomedical Optics 2 (1), 31-41 (January 1997) as well as Shankar P. Gopinath et al, J. Neurosurg. 83:438-444, 1995.